Fair Value Of Financial Assets And Liabilities (Fair Value Measurement Amounts For Assets And Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments in available-for-sale auction rate securities, fair value	$ 28	[1]	$ 29	[1]
Nuclear decommissioning trust fund equity securities	3,104		2,837
Nuclear decommissioning trust fund debt securities	1,432		1,405
Other long-term trading and available-for-sale equity securities	93	[2]	72	[2]
Other trading and available-for sale debt securities	634	[3]	602	[3]
Derivative assets	75	[2]	103	[2]
Assets, Fair Value Disclosure, Total	5,366		5,048
Derivative liabilities	(611)	[4]	(756)	[4]
Net Assets Fair Value, Total	4,755		4,292
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund equity securities	3,026		2,762
Nuclear decommissioning trust fund debt securities	356		317
Other long-term trading and available-for-sale equity securities	84	[2]	63	[2]
Other trading and available-for sale debt securities	94	[3]	40	[3]
Derivative assets	1	[2]	18	[2]
Assets, Fair Value Disclosure, Total	3,561		3,200
Derivative liabilities	(77)	[4]	(17)	[4]
Net Assets Fair Value, Total	3,484		3,183
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund equity securities	57		54
Nuclear decommissioning trust fund debt securities	1,027		1,040
Other long-term trading and available-for-sale equity securities	9	[2]	9	[2]
Other trading and available-for sale debt securities	540	[3]	562	[3]
Derivative assets	20	[2]	22	[2]
Assets, Fair Value Disclosure, Total	1,653		1,687
Derivative liabilities	(398)	[4]	(591)	[4]
Net Assets Fair Value, Total	1,255		1,096
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments in available-for-sale auction rate securities, fair value	28	[1]	29	[1]
Nuclear decommissioning trust fund equity securities	21		21
Nuclear decommissioning trust fund debt securities	49		48
Derivative assets	54	[2]	63	[2]
Assets, Fair Value Disclosure, Total	152		161
Derivative liabilities	(136)	[4]	(148)	[4]
Net Assets Fair Value, Total	16		13
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments in available-for-sale auction rate securities, fair value	3	[5]	3	[5]
Nuclear decommissioning trust fund equity securities	1,734		1,592
Nuclear decommissioning trust fund debt securities	785		762
Assets, Fair Value Disclosure, Total	2,522		2,357
Derivative liabilities	(5)	[6]	(12)	[6]
Net Assets Fair Value, Total	2,517		2,345
Duke Energy Carolinas [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund equity securities	1,663		1,523
Nuclear decommissioning trust fund debt securities	180		155
Assets, Fair Value Disclosure, Total	1,843		1,678
Net Assets Fair Value, Total	1,843		1,678
Duke Energy Carolinas [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund equity securities	50		48
Nuclear decommissioning trust fund debt securities	556		559
Assets, Fair Value Disclosure, Total	606		607
Net Assets Fair Value, Total	606		607
Duke Energy Carolinas [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments in available-for-sale auction rate securities, fair value	3	[5]	3	[5]
Nuclear decommissioning trust fund equity securities	21		21
Nuclear decommissioning trust fund debt securities	49		48
Assets, Fair Value Disclosure, Total	73		72
Derivative liabilities	(5)	[6]	(12)	[6]
Net Assets Fair Value, Total	68		60
Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund equity securities	1,369		1,245
Nuclear decommissioning trust fund debt securities	648		643
Other trading and available-for sale debt securities	60	[7]	57	[7]
Derivative assets	15	[8]	11	[8]
Assets, Fair Value Disclosure, Total	2,092		1,956
Derivative liabilities	(269)	[9]	(440)	[9]
Net Assets Fair Value, Total	1,823		1,516
Progress Energy [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund equity securities	1,363		1,239
Nuclear decommissioning trust fund debt securities	177		162
Other trading and available-for sale debt securities	20	[7]	17	[7]
Assets, Fair Value Disclosure, Total	1,560		1,418
Net Assets Fair Value, Total	1,560		1,418
Progress Energy [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund equity securities	6		6
Nuclear decommissioning trust fund debt securities	471		481
Other trading and available-for sale debt securities	40	[7]	40	[7]
Derivative assets	15	[8]	11	[8]
Assets, Fair Value Disclosure, Total	532		538
Derivative liabilities	(238)	[9]	(402)	[9]
Net Assets Fair Value, Total	294		136
Progress Energy [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	(31)	[9]	(38)	[9]
Net Assets Fair Value, Total	(31)		(38)
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund equity securities	894		811
Nuclear decommissioning trust fund debt securities	453		448
Other trading and available-for sale debt securities	4	[7]	3	[7]
Derivative assets	5	[8]	2	[8]
Assets, Fair Value Disclosure, Total	1,356		1,264
Derivative liabilities	(98)	[10]	(166)	[10]
Net Assets Fair Value, Total	1,258		1,098
Duke Energy Progress [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund equity securities	894		811
Nuclear decommissioning trust fund debt securities	123		119
Other trading and available-for sale debt securities	4	[7]	3	[7]
Assets, Fair Value Disclosure, Total	1,021		933
Net Assets Fair Value, Total	1,021		933
Duke Energy Progress [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund debt securities	330		329
Derivative assets	5	[8]	2	[8]
Assets, Fair Value Disclosure, Total	335		331
Derivative liabilities	(67)	[10]	(128)	[10]
Net Assets Fair Value, Total	268		203
Duke Energy Progress [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	(31)	[10]	(38)	[10]
Net Assets Fair Value, Total	(31)		(38)
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund equity securities	474		435
Nuclear decommissioning trust fund debt securities	196		194
Other trading and available-for sale debt securities	45	[11]	43	[11]
Derivative assets	10	[12]	9	[12]
Assets, Fair Value Disclosure, Total	725		681
Derivative liabilities	(167)	[13]	(270)	[13]
Net Assets Fair Value, Total	558		411
Duke Energy Florida [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund equity securities	468		429
Nuclear decommissioning trust fund debt securities	54		43
Other trading and available-for sale debt securities	5	[11]	3	[11]
Assets, Fair Value Disclosure, Total	527		475
Net Assets Fair Value, Total	527		475
Duke Energy Florida [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Nuclear decommissioning trust fund equity securities	6		6
Nuclear decommissioning trust fund debt securities	142		151
Other trading and available-for sale debt securities	40	[11]	40	[11]
Derivative assets	10	[12]	9	[12]
Assets, Fair Value Disclosure, Total	198		206
Derivative liabilities	(167)	[13]	(270)	[13]
Net Assets Fair Value, Total	31		(64)
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	19	[14]	59	[14]
Derivative liabilities	(94)	[9]	(38)	[9]
Net Assets Fair Value, Total	(75)		21
Duke Energy Ohio [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	8	[14]	48	[14]
Derivative liabilities	(72)	[9]	(15)	[9]
Net Assets Fair Value, Total	(64)		33
Duke Energy Ohio [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	2	[14]	2	[14]
Derivative liabilities	(8)	[9]	(8)	[9]
Net Assets Fair Value, Total	(6)		(6)
Duke Energy Ohio [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	9	[14]	9	[14]
Derivative liabilities	(14)	[9]	(15)	[9]
Net Assets Fair Value, Total	(5)		(6)
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale securities, equity securities, noncurrent	54	[1]	49	[1]
Available-for-sale securities, debt securities, noncurrent	29	[1]	29	[1]
Derivative assets	5	[15]	10	[15]
Assets, Fair Value Disclosure, Total	88		88
Derivative liabilities	(55)	[4]	(63)	[4]
Net Assets Fair Value, Total	33		25
Duke Energy Indiana [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale securities, equity securities, noncurrent	54	[1]	49	[1]
Derivative assets	1	[15]
Assets, Fair Value Disclosure, Total	55		49
Net Assets Fair Value, Total	55		49
Duke Energy Indiana [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale securities, debt securities, noncurrent	29	[1]	29	[1]
Assets, Fair Value Disclosure, Total	29		29
Derivative liabilities	(55)	[4]	(63)	[4]
Net Assets Fair Value, Total	(26)		(34)
Duke Energy Indiana [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	4	[15]	10	[15]
Assets, Fair Value Disclosure, Total	4		10
Net Assets Fair Value, Total	$ 4		$ 10

[1] Included in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.

[2] Included in Other within Current Assets and Other within Investments and Other Assets on the Condensed Consolidated Balance Sheet.

[3] Included in Other within Investments and Other Assets and Short-term Investments on the Condensed Consolidated Balance Sheets.

[4] Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets.

[5] Included in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.

[6] Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheet.

[7] Included in Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.

[8] Included in Other Current Assets within Current Assets and Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.

[9] Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities in the Condensed Consolidated Balance Sheets.

[10] Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities in the Condensed Consolidated Balance Sheets

[11] Included in Other within Investments and Other Assets in the Condensed Balance Sheets.

[12] Included in Other Current Assets within Current Assets and Other within Investments and Other Assets in the Condensed Balance Sheets.

[13] Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities in the Condensed Balance Sheets

[14] Included in Other within Current Assets and Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.

[15] Included in Other within Current Assets on the Condensed Consolidated Balance Sheets.